| Revision as of 21:42, 6 November 2006 editAndrew c (talk | contribs)Extended confirmed users31,890 edits "sometime" is important because the exact point when the brain and neurons begin working is debated← Previous edit | Revision as of 15:26, 21 December 2006 edit undo147.188.22.32 (talk) Updated the page to reflect recent publications and generally balanced the page to include arguments aginst the notion of fetal pain.Next edit → | ||
| Line 1: | Line 1: | ||
| '''Fetal pain''' is a subject of intense political and academic debate as part of the controversy over ]. Determining the stage of pregnancy at which a fetus is able to feel pain could have a significant effect on ]s and practices. | '''Fetal pain''' is a subject of intense political and academic debate as part of the controversy over ]. Determining the stage of pregnancy at which a fetus is able to feel pain could have a significant effect on ]s and practices. | ||
| Many scientists believe that a ] is able to feel pain {{ref|AboPain}} sometime during the pregnancy usually after 26 weeks gestation although the question of exactly when pain might be possible is disputed. Some academics argue that it appears as early as seven weeks after conception. Others claim that pain cannot be felt until the ] of pregnancy or until after birth. | |||
| Multiple nerve systems are involved in the sensation of ]. When the ] and ] are fully developed, noxious events trigger a nociceptive response including activation of the peripheral nerve fibres that relay information to dedicated pathways through the spinal cord and into multiple regions of the brain. Early in development, from about 12-18 weeks gestation, there is a complete link from the periphery to the thalamus in the brain and the fetus shows clear evidence of defensive reactions against tissue damage including hormonal and hemodynamic responses. After about 26 weeks gestation there is a complete link from the thalamus to the cortex of the brain. Cortical responses in premature babies of about 25 weeks gestation have been recorded during the usual heel lance procedure performed shortly after birth. In summary, there is good evidence that from about 26 weeks gestation the fetal brain can be considered a functional unit capable of processing noxious sensory input. | |||
| Multiple nerve systems are involved in the sensation of ]. When the ] and ] are fully developed, the sensation is triggered by ]s reacting to some stimulus. The resulting signal travels via the ] to nociceptors associated with the ]. It then travels up the spinal column to the ], and onward to the ], where it is finally interpreted as a painful sensation. | |||
| Several recent reviews have reached quite different conclusions as to whether this system is necessary and sufficient for pain experience in the fetus. Lee and colleagues, in their JAMA review, suggested that a cortical response can be equated with a painful experience. Derbyshire, however, argued that painful experience cannot be directly coded into the cortex because it is a subjective experience that is dependent upon developmental events that happen outside of the womb. | |||
| The different systems involved in pain develop at different stages of gestation. Nociceptors are present as early as seven weeks post-conception. The spinal column and the thalamus are functional at about thirteen weeks. However, the final necessary connections within the cerebral cortex are not developed until about the twenty-sixth week. Whether pain is possible before all the systems are developed and all the connections are made is one of the main questions of the fetal pain controversy. | |||
| Researchers who believe that a fetus can feel pain early, as soon as some of the necessary nerves are available, tend to support criminalization of abortion. There is some concern that strong views on both sides of the abortion debate may be influencing the interpretation of research findings. | |||
| == Medical opinions == | == Medical opinions == | ||
| Line 17: | Line 15: | ||
| In ], a working group appointed by the ] in the ] contradicted these findings, stating that "little sensory input" reaches the brain of the developing fetus before 26 weeks. "Therefore reactions to noxious stimuli cannot be interpreted as feeling or perceiving pain."{{ref label|AboPain|1|b}} | In ], a working group appointed by the ] in the ] contradicted these findings, stating that "little sensory input" reaches the brain of the developing fetus before 26 weeks. "Therefore reactions to noxious stimuli cannot be interpreted as feeling or perceiving pain."{{ref label|AboPain|1|b}} | ||
| In 2005, Mellor and colleagues reviewed several lines of evidence that suggested a fetus does not awake during it's time in the womb. If the fetus is asleep throughout gestation then the possibility of fetal pain is greatly minimised. | |||
| ⚫ | |||
| Mellor DJ, Diesch TJ, Gunn AJ, Bennet L. The importance of ‘awareness’ for understanding fetal pain. Brain Res Rev 2005;49:455-71. | |||
| ⚫ | Later in ], a ] of existing experiments undertaken by the ] concluded that the lack of functioning neurological pathways to a fetus' cererbral cortex before 26 weeks meant that it could not experience pain before then. The meta-study was criticised by pro-life groups who were suspicious of the prior involvement of several authors of the report. One directs an abortion clinic at ], while the lead author undertook legal work with ] for six months. | ||
| Lee SJ, Ralston HJP, Drey EA, Partridge JC, Rosen MA. Fetal pain: a systematic multidisciplinary review of the evidence. JAMA 2005;294:947-54. | |||
| In 2006, a clinical review published in the British Medical Journal concluded that pain is dependent upon cognitive and emotional developments that occur after birth: | |||
| "Theories of development assume that the early human mind begins with minimal content and gradually evolves into the rich experience of older children and adults. Although the view of a neonate as a blank slate, or tabula rasa, is generally rejected, it is broadly accepted that psychological processes have content concerning people, objects, and symbols, which lay in the first instance outside the brain. If pain also depends on content derived from outside the brain, then fetal pain cannot be possible, regardless of neural development". | |||
| Derbyshire SWG. Can fetuses feel pain? British Medical Journal 2006;332:909-12. | |||
| === Notes === | === Notes === | ||
Revision as of 15:26, 21 December 2006
Fetal pain is a subject of intense political and academic debate as part of the controversy over abortion. Determining the stage of pregnancy at which a fetus is able to feel pain could have a significant effect on abortion laws and practices.
Many scientists believe that a fetus is able to feel pain sometime during the pregnancy usually after 26 weeks gestation although the question of exactly when pain might be possible is disputed. Some academics argue that it appears as early as seven weeks after conception. Others claim that pain cannot be felt until the third trimester of pregnancy or until after birth.
Multiple nerve systems are involved in the sensation of pain. When the brain and nervous system are fully developed, noxious events trigger a nociceptive response including activation of the peripheral nerve fibres that relay information to dedicated pathways through the spinal cord and into multiple regions of the brain. Early in development, from about 12-18 weeks gestation, there is a complete link from the periphery to the thalamus in the brain and the fetus shows clear evidence of defensive reactions against tissue damage including hormonal and hemodynamic responses. After about 26 weeks gestation there is a complete link from the thalamus to the cortex of the brain. Cortical responses in premature babies of about 25 weeks gestation have been recorded during the usual heel lance procedure performed shortly after birth. In summary, there is good evidence that from about 26 weeks gestation the fetal brain can be considered a functional unit capable of processing noxious sensory input.
Several recent reviews have reached quite different conclusions as to whether this system is necessary and sufficient for pain experience in the fetus. Lee and colleagues, in their JAMA review, suggested that a cortical response can be equated with a painful experience. Derbyshire, however, argued that painful experience cannot be directly coded into the cortex because it is a subjective experience that is dependent upon developmental events that happen outside of the womb.
Medical opinions
In 1997, Dr. Robert White, director of the Division of Neurosurgery and Brain Research Laboratory at Case Western Reserve School of Medicine and a member of the Vatican's Pontifical Academy of Sciences , gave testimony before the House Constitution Subcommittee of the Congress of the United States. He stated that, at 20 weeks' gestation, the fetus "is fully capable of experiencing pain...Without question, all of this is a dreadfully painful experience for any infant subjected to such a surgical procedure."
His assertions were supported by Dr. Paul Ranalli, a neurologist at the University of Toronto, who has cited several observations to support the belief that a fetus can experience pain. These include observing a fetus "withdraw from painful stimulation", and the fact that stress hormones detected in adults observing pain has also been found in the blood samples of aborted fetuses. Dr. Paul Ranalli is a member on the Advisory Board of the deVeber Institute for Bioethics and Social Research, a pro-life organization (See end of this PDF newsletter).
In 2001, a working group appointed by the Royal College of Obstetricians and Gynecologists in the United Kingdom contradicted these findings, stating that "little sensory input" reaches the brain of the developing fetus before 26 weeks. "Therefore reactions to noxious stimuli cannot be interpreted as feeling or perceiving pain."
In 2005, Mellor and colleagues reviewed several lines of evidence that suggested a fetus does not awake during it's time in the womb. If the fetus is asleep throughout gestation then the possibility of fetal pain is greatly minimised.
Mellor DJ, Diesch TJ, Gunn AJ, Bennet L. The importance of ‘awareness’ for understanding fetal pain. Brain Res Rev 2005;49:455-71.
Later in 2005, a meta-analysis of existing experiments undertaken by the Journal of the American Medical Association concluded that the lack of functioning neurological pathways to a fetus' cererbral cortex before 26 weeks meant that it could not experience pain before then. The meta-study was criticised by pro-life groups who were suspicious of the prior involvement of several authors of the report. One directs an abortion clinic at San Francisco Hospital, while the lead author undertook legal work with NARAL Pro-Choice America for six months.
Lee SJ, Ralston HJP, Drey EA, Partridge JC, Rosen MA. Fetal pain: a systematic multidisciplinary review of the evidence. JAMA 2005;294:947-54.
In 2006, a clinical review published in the British Medical Journal concluded that pain is dependent upon cognitive and emotional developments that occur after birth:
"Theories of development assume that the early human mind begins with minimal content and gradually evolves into the rich experience of older children and adults. Although the view of a neonate as a blank slate, or tabula rasa, is generally rejected, it is broadly accepted that psychological processes have content concerning people, objects, and symbols, which lay in the first instance outside the brain. If pain also depends on content derived from outside the brain, then fetal pain cannot be possible, regardless of neural development".
Derbyshire SWG. Can fetuses feel pain? British Medical Journal 2006;332:909-12.
Notes
- "Can a fetus feel pain?". Retrieved December 14.
{{cite web}}: Check date values in:|accessdate=(help); Unknown parameter|accessyear=ignored (|access-date=suggested) (help)
References
Anand, K.J.S. & P.R. Hickey. "Pain and Its Effects In the Human Neonate and Fetus." New England Journal of Medicine. Vol. 317, #21 (19.November.1987): pp. 1321-1329 HTML version
External links
- Pro-life site presenting case for fetal pain from second month of pregnancy: HTML version.
- A review of clinical evidence concerning fetal pain, JAMA. 2005;294:947-954. HTML version
- 109th Congress, U.S.A. "Unborn Child Pain Awareness Act of 2005." 1st Session, S.51. (January, 2005). PDF version, HTML version
- National Right to Life Committee's webpage of testimonies regarding fetal pain. HTML version